wood movement - a little OT

[Larry Blanchard]

I've been having an email discussion with several model railroaders who are convinced that wood changes length with humidity. It must, because their track is developing kinks :-).

I've quoted websites and books that prove they're wrong, but it doesn't faze the true believers. Seems politics and religion aren't the only areas in which opinion trumps facts :-).

OK, it does move a little - according to the wood handbook 0.1%-0.2% from totally green to over dry. That's about 0.1" in 8'. And I doubt they're using green wood :-).

OTOH, some of the same folks are convinced that Homasote (a pressed paper product) does not move from wet to dry.

You meet the nicest people on a keyboard :-).

[dpb]

...

Depending on which particular Homasote(tm) product, it's not processed/recycled paper base but wood fiber and they're not bad wrong on expansion properties...

...

The last is pretty much equivalent to longitudinal wood movement.

Would have to see the construction techniques, materials and know the actual conditions to have a clue on the actual cause(s) behind reported incidents. One would guess combination of things in most cases the most likely being design/construction/environmental control issues w/ materials coming in there somewhere.

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[Zz Yzx]

I wonder if they've considered the substrate the track is attached to. Also, does the track unkink when it gets drier?

-Zz

[Artemus]

Have they ruled out the metal rails of the track changing length with changing temperature? Some RR'ers solder the track section joints for better electrical performance and some don't. Those that don't have some expansion room in the joints to accommodate the rails delta-L. Art

[Larry Jaques]

On Fri, 4 Jun 2010 16:48:04 +0000 (UTC), Larry Blanchard wrote the following:

So, have you sold them a januwine Wood Shrinking Unit yet, LB?

Say "Halelujah!" and pass the mashed potatoes.

P.S: It's nice to know that the Wreck isn't the only source of cracked info.

-- It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change. -- Charles Darwin